1. Field of the Invention
The present invention relates to a illumination package, and more particularly to a light emitter coupled with an optical lens able to redirect light to a direction approximately perpendicular to the longitudinal axis passing through a horizontal surface of the illumination package.
2. Description of the Related Art
FIG. 1 illustrates a conventional Light Emitting Diode (LED) package 10 that includes an optical lens 11, a package base 12, and a LED chip 13. The LED package 10 has a longitudinal axis 15 passing through the center of the optical lens 11. The LED chip 13 is positioned on the package base 12. The package base 12 may have a cup (not shown) with a reflector (not shown) to reflect light emitted from the bottom and sides of the LED chip 13 towards the observer.
The optical lens 11 is coupled to the LED chip 13 to receive and redirect light emitted from the LED chip 13. The optical lens 11 may have a recess 14 to adapt the LED chip 13. The light entering through the recess 14 of the optical lens 11 may travel in two main light paths. The first light path LP1 is that the light emitted from the LED chip 13 travels to the surface 1102 and be total-internal-reflected to exit through sidewall 1101 at approximately 90 degree to the longitudinal axis 15. The second light path LP2 is that the light emitted from the LED chip 13 travels towards the sidewall 1101 at an angel causing total internal reflection or a reflection from the sidewall 1101 to exit the optical lens 11 at an angle not close to perpendicular to the longitudinal axis 15. The first light path LP1 is preferable to generate an efficient side emitting light, while the second light path LP2 may cause a light spot, which is not desirable with the observer.
A need exists for an LED package or illumination device to reduce its entire size by coupling a shallow optical lens and avoid light spots suffered by the observer. A need also exists for an LED package or illumination device to provide uniform colored light.